<template>
  <div class="upload-file">
    <el-upload
      :action="uploadFileUrl"
      :before-upload="handleBeforeUpload"
      :file-list="fileList"
      :limit="1"
      :on-error="handleUploadError"
      :on-exceed="handleExceed"
      :on-success="handleUploadSuccess"
      :show-file-list="false"
      :headers="headers"
      class="upload-file-uploader"
      ref="upload"
    >
      <!-- 上传按钮 -->
      <el-button size="mini" type="primary">选取文件</el-button>
      <template #tip v-if="showTip">
        <!-- 上传提示 -->
        <div class="el-upload__tip">
          请上传
          <template v-if="fileSize"> 大小不超过 <b style="color: #f56c6c">{{ fileSize }}MB</b> </template>
          <template v-if="fileType"> 格式为 <b style="color: #f56c6c">{{ fileType.join("/") }}</b> </template>
          的文件
        </div>
      </template>
    </el-upload>

    <!-- 文件列表 -->
    <transition-group class="upload-file-list el-upload-list el-upload-list--text" name="el-fade-in-linear" tag="ul">
      <li :key="file.uid" class="el-upload-list__item ele-upload-list__item-content" v-for="(file, index) in list">
        <el-link :href="file.url" :underline="false" target="_blank">
          <span class="el-icon-document"> {{ getFileName(file.name) }} </span>
        </el-link>
        <div class="ele-upload-list__item-content-action">
          <el-link :underline="false" @click="handleDelete(index)" type="danger">删除</el-link>
        </div>
      </li>
    </transition-group>
  </div>
</template>

<script lang="ts">
import { defineComponent, reactive, toRefs, computed } from 'vue'
import { ElMessage } from 'element-plus'
import config from '@/config'
import { getToken } from '@/utils/auth'

interface HeadersType {
  Authorization: string;
}
interface DataType {
  uploadFileUrl: string | undefined;
  headers: HeadersType;
  fileList: Array<any>;
}

export default defineComponent({
  name: 'FileUpload',
  props: {
    // 值
    value: [String, Object, Array],
    // 大小限制(MB)
    fileSize: {
      type: Number,
      default: 5
    },
    // 文件类型, 例如['png', 'jpg', 'jpeg']
    fileType: {
      type: Array,
      default: () => ['doc', 'xls', 'ppt', 'txt', 'pdf']
    },
    // 是否显示提示
    isShowTip: {
      type: Boolean,
      default: true
    }
  },
  setup(props, context) {
    const data = reactive<DataType>({
      uploadFileUrl: config.baseURL + '/common/upload',
      headers: {
        Authorization: 'Bearer ' + getToken()
      },
      fileList: []
    })
    const showTip = computed<boolean>(() => {
      return props.isShowTip && (!!props.fileType || props.fileSize)
    })
    const list = computed(() => {
      let temp = 1
      if (props.value) {
        // 首先将值转为数组
        const list = Array.isArray(props.value) ? props.value : [props.value]
        // 然后将数组转为对象数组
        return list.map((item) => {
          if (typeof item === 'string') {
            item = { name: item, url: item }
          }
          item.uid = item.uid || new Date().getTime() + temp++
          return item
        })
      } else {
        // eslint-disable-next-line vue/no-side-effects-in-computed-properties
        data.fileList = []
        return []
      }
    })
    data.fileList = list.value

    const handleBeforeUpload = (file: File) => {
      // 校检文件类型
      if (props.fileType) {
        let fileExtension = ''
        if (file.name.lastIndexOf('.') > -1) {
          fileExtension = file.name.slice(file.name.lastIndexOf('.') + 1)
        }
        const isTypeOk = (props.fileType as Array<string>).some((type: string) => {
          if (file.type.indexOf(type) > -1) return true
          if (fileExtension && fileExtension.indexOf(type) > -1) return true
          return false
        })
        if (!isTypeOk) {
          ElMessage({
            message: `文件格式不正确, 请上传${props.fileType.join('/')}格式文件!`,
            type: 'error'
          })
          return false
        }
      }
      // 校检文件大小
      if (props.fileSize) {
        const isLt = file.size / 1024 / 1024 < props.fileSize
        if (!isLt) {
          ElMessage({
            message: `上传文件大小不能超过 ${props.fileSize} MB!`,
            type: 'error'
          })
          return false
        }
      }
      return true
    }

    const handleExceed = () => {
      ElMessage({
        message: '只允许上传单个文件',
        type: 'error'
      })
    }

    const handleUploadError = () => {
      ElMessage({
        message: '上传失败, 请重试',
        type: 'error'
      })
    }

    const handleUploadSuccess = (res: any) => {
      ElMessage({
        message: '上传成功',
        type: 'error'
      })
      context.emit('input', res.url)
    }

    const handleDelete = (index: number) => {
      data.fileList.splice(index, 1)
      context.emit('input', '')
    }

    const getFileName = (name: string) => {
      if (name.lastIndexOf('/') > -1) {
        return name.slice(name.lastIndexOf('/') + 1).toLowerCase()
      } else {
        return ''
      }
    }
    return {
      getFileName,
      handleDelete,
      handleUploadSuccess,
      handleUploadError,
      handleExceed,
      handleBeforeUpload,
      showTip,
      ...toRefs(data)
    }
  }
})
</script>

<style scoped lang="scss">
.upload-file-uploader {
  margin-bottom: 5px;
}
.upload-file-list .el-upload-list__item {
  border: 1px solid #e4e7ed;
  line-height: 2;
  margin-bottom: 10px;
  position: relative;
}
.upload-file-list .ele-upload-list__item-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: inherit;
}
.ele-upload-list__item-content-action .el-link {
  margin-right: 10px;
}
</style>
